The Big Block Engine

The words big-block roll off my tongue with pause and reverence. Big-block is the heavyweight, the large caliber, the big show, the predatory carnivores of the asphalt jungle. The term denotes the top tier, the upper classmen of the muscle car game.

There are plenty of high-powered, high-winding small-blocks that can, under the right circumstances, outshoot a big-block. But generally speaking, cubes rule, and big-blocks have more cubes that any other passenger car on earth.

When the expansion of car dimensions and the demand for more power options necessitated engines larger than the mid-’50s V-8s, engineers went to work designing all-new engines capable of 400 ci and more.

Ford’s FE (Ford Edsel) big-block arrived for 1958 as a 332 or 352, as did Chevrolet’s new W-engine, displacing 348 cubes. Chrysler’s 392 Hemi showed up a year earlier and was replaced by the 413 wedge for 1959. The big-blocks had landed.

Each grew through stages of development, peaking with legendary engines like the 427 8V, ZL1, Boss 429, 440 Six Pack, 455 W-30, 454 LS6, 455 Stage 1, and 455 Super Duty. They were like nothing the world had ever seen. Europe had sporty inline 4s and 6s, and a V-12 here and there, but these were small-displacement engines built for rpm, and completely different from the thumpin’ big-blocks in power and personality.

From the second you spin the key, you know the big-block is in a league of its own. The starter sounds different. It’s spinning a lot of cubes against lots of compression and timing. When it starts, it has a different sound at the tailpipe. Rev it and it’s got a different feel. Drop it in gear and it engages with an impact you feel throughout the whole car. Just touch the gas pedal and the car steps out. You’re in the big leagues.

Megacube engines will never be equaled

High points came early and kept coming. Pontiac’s 421 SD was a beast, developed when government restrictions did not exist. Twin Carter AFBs, a stout cam, and magnificent exhaust manifolds were among the more artful components. Pontiac blocks remained in the same family, so there’s no hard break between big-block and small-block. The terms don’t cleanly apply, so it’s loosely acknowledged by displacement.

Chevrolet’s ’63-’64 425hp 409 brought haymaker power to one of the best-looking fullsize Impalas ever. But none were better engineered or accomplished in competition than Ford’s 427.

Chevrolet ditched the 409 for a better-breathing Mark IV big-block for 1965 and wasted no time extracting performance from it. A rare option was the 396/425hp engine, installed in a handful of fullsize cars and Corvettes. The 396 was cubed up to 427 in the ’66 model year, and for a few months the L72 option was rated at 450 hp before being quietly rerated to 425 without explanation.

Also for 1966, Mopar released a new 440 and the ultimate muscle car engine, the Street Hemi.

The late ’60s saw a shift among the power players. Ford dropped its 427 in favor of a simpler, more streetable 428. A new-gen big-block, the 385-series debuting with 429 ci, was being produced at the Lima, Ohio, plant, and featured modern block design, canted valves, and stud-mounted rockers. A wild, Hemified Boss version made headlines in the Mustang; and wedge-head CJ, Super CJ, and Ram Air versions would arrive for 1970.

Olds broke the corporate restriction limiting A-Body intermediates to 400 ci with the ’68 Hurst/Olds, packing a hybrid 455 and a cover story that the engines were installed at Demmer Tool, an outside contractor, instead of the Lansing plant where assembly actually took place.

Mother Mopar topped its 440 with a trio of Holleys under a liftoff hood, creating one of the best street/strip cars of all time.

In 1970 GM’s displacement restriction was lifted. For a couple of years, aggressive performance engineering converged with huge displacement as the muscle car market reached an unforgettable zenith. Sales in 1971 were off, and by 1972 the curtain was closing. By 1975 the big-block as we knew it was all but extinct.

Even so, there’s just no thrill like putting your foot into the old rubber gas pedal and uncorking the big-block’s unique torque explosion. The vibe, the charisma, the mystique, the old, raw, low-tech, high-performance megacube engines will never be equaled.